Sustainability may influence consumer choice in the market place. Consequently, there is a movement toward providing products that may have a reduced impact on the environment. In the field of liquid laundry detergents, this has led to the development of new formulations that can be effective at relatively low washing temperatures. These new formulations are desirable since utilizing lower washing temperatures can save energy as well as prolong the useful life of fabrics.
In some instances, new detergent formulations are concentrated from the traditional dilute liquid form into a concentrated liquid or gel form. These so-called “compacted” detergents are also desirable since they require less packaging material, are easier to transport in bulk and occupy less space on the store shelf.
Based upon the foregoing, it would be desirable to combine both compaction of a liquid laundry detergent with superior low temperature performance. However, current compaction methods may not provide for concentrated detergents that rapidly and effectively dissolve at lower than normal wash temperatures.
Compaction of liquid laundry detergents is currently accomplished using several means. One means is by increasing surfactant concentrations and removing organic solvent. The resulting detergents may derive rheological characteristics from the surfactant and are often referred to as being “internally structured”. However, internally structured liquid laundry detergents may be extremely viscous and phase unstable. Moreover, internally structured liquid laundry detergents may become even more viscous upon dissolution in a laundry bath. Thus these compacted detergents may not be particularly effective for low temperature laundering in which dissolution may be an issue even for non-compacted liquid laundry detergents. This may particularly be the case when short washing machine cycles are utilized.
Another means of compacting liquid laundry detergents is to maintain a proportion of organic solvents in the detergent while removing water. This approach is consistent with the formulation of detergent into soluble film packets. Typical water levels in such detergents are as low as from about 5 to 10% by weight so as to avoid dissolution of the soluble, e.g., PVA film during storage of the detergent. However, this formulation approach does not take into account the high cost of converting many laundry detergent ingredients, which are commercially available in a form having a large proportion of water, into dry or near-to-dry forms. In addition to the cost of removing water from these ingredients, the manufacturing processes for these concentrated detergents may need to be substantially modified so as to be able to process dry or highly viscous raw materials into the detergent.
In many geographies, there is furthermore a need to include builders in the detergent formulation for their known water-hardness management characteristics. However builders place further constraints on the ability to compact a detergent owing to their salting-out effects (in the case of citrate) or their viscosifying effects on surfactants (in the case of fatty acid builders). Yet, it is desirable to include such materials in compact laundry gel formulations.
Therefore there remains a need to provide cost-effective detergent formulations, and the associated processes for making them, that will provide both the benefits of substantial compaction of the detergent and that will achieve desired performance parameters at low temperatures, particularly via effective dissolution and in the presence of dissolved builders. In one aspect, the present invention addresses this problem without resorting to the very low water levels that are typical of some liquid detergents that are provided in a unitized dose.
In another aspect intimately related to the foregoing problems, there is an ongoing need for a process for manufacturing a concentrated aqueous liquid or gel-form laundry detergent comprising at least 10% of at least one anionic nonsoap surfactant; at least 0.1% of other surfactants (especially nonionic surfactants) such that the total surfactant level is at least 20%; and such that the detergent comprises no more than 15% organic non-aminofunctional solvent, wherein said detergent is free from phase splits.